This application is related to and claims priority from Japanese Patent Applications No. 2001-203660 filed on Jul. 4, 2001, and No. 2001-346242 filed on Nov. 12, 2001, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a heat storage tank in which a fluid is thermally insulated and stored, and is suitably applied to a vehicle heat storage tank in which cooling water (hot water) for cooling a vehicle engine is thermally insulated and stored.
2. Description of Related Art
For example, in a heat storage tank disclosed in JP-A-10-71840, a mixture protection plate having plural holes is provided around a water inlet, so that it can restrict engine-cooling water (hot water) in a tank body from being forcibly agitated and mixed due to an injection water from the water inlet.
However, in this heat storage tank, the following problems have been found by detail studies performed by the present inventors. Here, opening areas of the water inlet and a water outlet provided in the tank body are need to be made as small as possible to improve thermal insulation performance of the heat storage tank. When the opening area of the water inlet is made smaller, a flow speed of injection water from the water inlet into the tank body becomes higher in a case that an amount of water flowing into the tank body is large. Therefore, the injection water may directly passes through the holes provided in the mixture protection plate while its flowing direction is not largely changed by the mixture protection plate. Accordingly, water in the tank body is stirred, and forced convention of water in the tank body is generated.
In view of the above problem, it is an object of the present invention to provide a heat storage tank which can effectively prevent a fluid in a tank body from being mixed due to a fluid injection from a discharge port even when the fluid flowing from the discharge port into the tank body has a high speed.
According to the present invention, in a heat storage tank, a first pipe member defining an introduction passage has a discharge port from which a fluid introduced through the introduction passage is injected into a tank body, a collision member is disposed in the tank body so that the fluid flowing from the discharge port collides with the collision member, a second pipe member defining a discharge passage has an introduction port from which the fluid in the tank body is introduced to be discharged outside the tank body through the discharge passage. The introduction port is positioned in the tank body at a side opposite to the discharge port with respect to the collision member. In addition, the collision member includes a shield portion disposed opposite to the discharge port to be separated from the discharge port by a predetermined dimension, and a guide portion, extending from the shield portion to a side of the discharge port, for guiding the fluid flowing along the shield portion toward a side of the discharge port. Accordingly, even when the flow speed of the fluid flowing from the discharge port is high, it can effectively prevent the fluid in the tank body from being mixed due to the fluid flowing from the discharge port. Thus, heat-storage performance of the fluid in the tank body can be improved.
Preferably, a mixture protection plate, for preventing the fluid in the tank body from being mixed due to the fluid flowing from the discharge port, is provided to have a plurality of through holes through which the fluid flowing from the discharge port flows. In addition, the mixture protection plate is disposed between the collision member and an inner surface of the tank body. Therefore, the fluid from the discharge port passes through the through holes of the mixture protection plate after colliding with the shield portion and after being guided by the guide portion. Accordingly, it can further effectively prevent the fluid in the tank body from being mixed due to the injection fluid from the discharge port.
On the other hand, according to the present invention, a plate-like shield portion is disposed in the tank body, instead of the collision member. In this case, the shield portion includes a collision wall surface with which the fluid flowing out from the discharge port collides, and a guide wall surface extending from the collision wall surface for guiding the fluid after colliding with the collision wall surface. The collision wall surface is disposed to face the discharge port and to be separated from the discharge port by a predetermined distance, and the guide wall surface is provided such that the fluid after colliding with the collision wall surface is prevented from directly flowing toward the introduction port. In addition, the introduction port and the discharge port are positioned at both opposite sides relative to the shield portion, and the collision wall surface and the guide wall surface of the shield portion have a moment center (G) that is located at a position separated from the discharge passage. Accordingly, it can effectively prevent the fluid in the tank body from being mixed due to the fluid injection from the discharge port.
Preferably, the moment center (G) is located at a position offset to a side of the discharge passage relative to the introduction passage. Therefore, the fluid after colliding with the collision wall surface can be effectively guided by the guide wall surface.